Integrated illumination and imaging system

ABSTRACT

A fiber optic endoscope which uses a bundle of coherent fiber to convey both an optical image in one direction and illumination light in the other direction. A fraction of the optical fibers are used for the illumination, and others of the fibers are used for the image. Notched fibers can be used for the illumination.

This is a continuation of application Ser. No. 08/890,803 filed on Jul.11, 1997, now U.S. Pat. No. 6,013,025. This application claims benefitto provisional application 60/022,023 filed on Jul. 11, 1996.

FIELD OF THE INVENTION

The present application describes an integrated illumination and imagingsystem. In one form, these concepts are particularly adapted for usewith an endoscope which has the capacity to illuminate a site ofinvestigation and transmit an image of that site by an-image carryingtransmission medium.

BACKGROUND OF THE INVENTION

Micro invasive surgery has a goal of minimizing the amount of damagecaused during surgery. Some surgical procedures, for example, can beobviated by using an endoscope through a small incision. The size of theincision, therefore, depends on the size of the endoscope. One importantfeature of an endoscope, therefore, is its size. Since many endoscopesrequire a separate light guide, this increases the size of theendoscope.

Current endoscopes often use some type of illumination bundles or lightguides to couple light to a site of viewing. The site of viewing is thenimaged by appropriate receiving of the coupled light that is reflectedby the area of the viewing site.

The present application describes a system that eliminates the need fora separate light guide and thereby reduces the requisite, probedimensions for a desired image size. Like current endoscopes, endoscopesusing this new technique are safe to introduce into the human body foruse in minimally invasive surgery. One application of this device is inthe area of root canal procedures in dentistry, although this systemcould similarly be used in other kinds of surgery.

International Patent Application No. WO 91/15793, by Acosta, et al.,discloses an endoscope in which light is transmitted to and from ananatomical site. One embodiment of the Acosta, et al. endoscope includesa plastic optical fiber assembly in which light is transmitted to thedistal end of the endoscope along the periphery of the fiber assemblyitself. Imaging light is transmitted back to the proximal end through acentral multi-fiber bundle.

Another embodiment of the Acosta, et al. application discloses a plasticoptical fiber assembly in which illuminating light is directed through apredetermined portion of the multi-fiber bundle. The balance of thebundle is.dedicated to transmitting imaging light.

An alternative embodiment of the Acosta, et al. Application described anendoscope in which a beam splitter directs light across the entire faceof the multi-fiber bundle. The returning imaging light is alsotransmitted through the entire crosssectional area of the bundle throughthe beam splitter to a viewing portion of the endoscope, which isproximal to the beam splitter.

SUMMARY OF THE INVENTION

The inventors recognized a need for an illumination and imaging devicewhich does not require a predetermined subset of fibers to be dedicatedto transmitting either illuminating or imaging light. There is a furtherneed for a self-filtering illumination and imaging device in whichvariable and dynamically changing portions of the multi-fiber bundletransmit either illuminating or imaging light.

An illuminating and imaging system of this system enables alternatefunctions of illuminating and imaging transmissions to be separatelyapplied to non-dedicated, dynamically alterable subsets of themulti-fiber image bundle;

will function using any type of image carrying transmission medium withpartitioned or pixeled capability;

enables all fibers of a multi-fiber image bundle to serve in eitherillumination or image transmission;

needs no separator or additional cladding between fiber portions of theimage bundle;

non-simultaneously uses all portions of a fiber optic bundle for bothillumination and image transmission; and

functions as a self-filtering system due to the placement of the lightemitting element with respect to the fibers which are transmittingilluminating light, thereby eliminating a sensation of glare when theimage is viewed or recorded.

Main advantages to this system over those proposed previously include:

1. Removal of light guides to make the bundles smaller and thereforeless invasive;

2. Reduction of the complexity of a given endoscope, which reduces thedifficulty and the cost of its manufacture; and

3. Removal of the light guides allows the entirety of an endoscope'scross sectional area to be devoted to the image bundle. Therefore, anendoscope operating by means of this proposed system can produce ahigher resolution image than conventional endoscopes of equalcross-sectional area.

We have considered multiple methods of implementing this dual functionbundle. They include the following:

1. Stationary Light Channeling

Channeling Above Bundle

2. Stationary Light Channeling

Channeling Within Bundle

3. Oscillating Light Channeling

4. Rotary Light Channeling

Rotation on Axis with Bundle

Light Sources Stationary

5. Rotary Light Channeling

Rotation on Axis with Bundle

Light Sources Rotate with Channeling Devices

6. Rotary Light Channeling

Rotation on a Parallel Axis with Bundle Axis

Light Sources Stationary

7. Cantilever Beam

Bending within the illumination plane

Light Source(s) Stationary

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be described withreference to the accompanying drawings, wherein:

FIG. 1 shows a general drawing of the endoscopic device;

FIGS. 2A and 2B show a first embodiment operating to channel the lightabove the bundle;

FIGS. 3A and 3B shows a device which channels with the bundle;

FIG. 4 shows an endoscope with an image bundle that alternates functionsbetween illumination and image transmission;

FIG. 5 shows a system rotating on axis with the bundle;

FIG. 6 shows an embodiment with additional light sources that rotate;

FIG. 7 shows an embodiment operating to rotate on a parallel axis to thebundle axis;

FIG. 8 shows a Cantalever beam system;

FIG. 9 shows an endoscope with prisms;

FIGS. 10-A, 10-B and 10-C shows an endoscope with prismatic choppingwheels;

FIGS. 11-A, 11-B and 11-C shows an endoscope with fiber optic guide;

FIG. 12 shows a Cantalever beam with fiber like channels;

FIG. 13 shows a fiber light conductor mounted to the beam.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An endoscope 30 of the preferred embodiment is depicted in FIG. 1 asimaging an anatomical site 32 whose image is desired to be detected. Thesystem operates by discretely projecting radiation, e.g., light, througha portion of a light transmission device. The preferred embodiment usesthe fibers 42 in the image bundle 44 of a fiber optic endoscope 30. Thissystem operates to remove thel necessity of separate light guides forillumination. The outer surface of the image bundle represents the holesize that needs to be made in order to insert the endoscope device.

A light illuminating device is effected by gathering light from externallight source 34 by light focusing device 36, and coupling that lightinto light channeling device 38. Light is then focused on a specificlocation or locations of image bundle 42 of endoscope 30 at its proximalend 44. Light focusing from light channeling device 38 may beincorporated directly into image bundle 42, or may be accomplished by agradient index (GRIN) lens 46 mounted to the proximal end 44 of fiberoptic bundle 44. The exposed portions of the bundle then carry lightfrom the proximal end to distal end 48 of endoscope 30, where theaccumulated light then illuminates the site of interest 32. Theremainder 50 of bundle 42 having its fibers unexposed to light at theproximal end, collect light reflected from the surfaces in the site ofinterest and carry it to proximal end 44 of endoscope 30. That light isthen magnified by camera optics 52 and collected by recording device 54,such as a digital video camera.

Embodiment 1. Stationary Light Channeling

This first embodiment is shown in FIGS. 2A and 2B, and uses theoperation of channeling above bundle.

Endoscope 30 includes light channeler 38 permanently mounted above theportion of the GRIN 46 or the image bundle. Light channeler is dedicatedto illumination. Light from external source 34 is focused by focusingdevice 36 and aimed at light channeler 38, which then transmits thislight onto the portion 56 of the bundle over which it is located. Inthis version of the device, section 56 of the image bundle located belowthe channeler 38 is permanently dedicated to illumination. The imagereceiving device records an image proximate distal end 48 of bundle 42partially obscured by light channeler 38.

Embodiment 2.

The second embodiment uses stationary light channeling, and is shown inFIGS. 3A and 3B. This operates to carry out channeling with the bundle.

Endoscope 60 includes channeling device 61 integrated within the bundle.Channeler 61 is formed by notch 62 cut into outside wall 64 of bundle66. Notch 62 has the proper geometry to receive light from direct lightsource 34 and divert the light toward the distal end of bundle 66. Lightreceived from notch 62 travels through bundle 66. This system uses theexposed fibers 68 as being permanently dedicated to illumination. FIG.3B shows that light channeling may be accomplished by one or morenotches 62 placed in bundle wall 64, which expose one or more sets offibers 68 to illuminating light.

Embodiments 1 and 2 differ from current endoscope technology byeliminating the need for light guides for illumination. This is done bypermanently dedicating a section of the image bundle fibers to serve thefunction of illuminating the sight of examination at the distal end ofendoscope.

The remaining embodiments, unlike embodiments 1 and 2, use lightchanneling devices are in motion with respect to the fiber optic bundlethey are illuminating, and the device used to record the image (thecamera). The channelers at a given instant in time obscure the bundlefrom view as do those in embodiment 1, yet the portion they obscure isnot the same over time. The motion of the channeler(s) is fast enoughthat the recorded image appears like an image seen through a propelleror ventilation fan in motion.

At any given moment, the portion of the image bundle exposed to thelight channeling device may range from 100% to 0%. Equivalently, at anygiven moment, the portion of the image bundle exposed to the opticalrecording device may range from 0% to 100%, but in practice will be lessthan the full range of the multiplexed use of the device, the opticalrange between about 30% and 70%.

As will be appreciated, the oscillation or rotation rates of theremaining embodiments lie within the range of the sampling rate of thedetector.

Embodiment 3. Oscillatory Light Channeling

Endoscope 80 shown in FIG. 4 differs from embodiments 1 and 2 in thatsections of GRIN lens 46, hence image bundle 42, alternate functionsbetween illumination and image transmission. One or more lightchannelers 82 oscillate as shown by arrow 84. At a given instant,whatever portion of the bundle is located directly below the lightchanneler transmits light to a site of interest for illumination, whileat other times the same portion provides image transmission. As withembodiments 1 and 2, the channeler receives light from a fixed externallight source.

Embodiment 4. Rotary Light Channeling

This embodiment is shown in FIG. 5. The system described operates tocarry out rotation on Axis with Bundle, and using stationary lightSources.

Endoscope 90 employs one or more reflectors (or channelers) 92 rotatingabout the bundle axis 94 as shown by arrow 96. Rotation of reflectors 92in this manner provides for illumination to different sections of GRINlens 46, hence image bundle 42 (not shown), at different times. In thisembodiment, light is provided by one or more fixed external sourcesappropriately aimed and focused onto the reflectors 92.

Embodiment 5. Rotary Light Channeling

FIG. 6 shows this embodiment using rotation on Axis with Bundle, andlight Sources Rotate with Channeling Devices.

In endoscope 100, one or more light sources 102 are dedicated tochannelers 106. That is, these endoscopes rotate as depicted by arrows108 along with channelers 106 over GRIN lens 46, hence bundle 42, out ofthe range of view of the image recording device (not shown).

Embodiment 6. Rotary Light Channeling

FIG. 7 shows this embodiment using Rotation on a Parallel Axis withBundle Axis, with stationary light Sources Stationary endoscope 120includes channelers 122 which rotate about axis 124 which is parallel toaxis 126 of image bundle 42, yet offset by some fixed distance 128.Illumination plane 130 is located some fixed distance above image bundle42 and a fixed distance below the image recording device (not shown). Asingle light source 132, located at a predetermined location withinillumination plane 130, is aimed at image bundle axis 126. As achanneler 122 passes over image bundle 42 in its orbital travel 134,channeler 122 collects light from the source 132 and directs the lightonto portion 136 of bundle 42 over which channeler 122 is traveling.

Embodiment 7. The Cantilever Beam

The concept of the cantilever beam, which bends with the illuminationplane using a stationary light Source, is shown in FIG. 8.

Endoscope 140 uses a cantilever light beam 142 which extends from lightsource 144. Beam 142 cyclically deflects light from its neutral axis 146into proximal end 44 of image bundle 42. The path of deflection 150exists within illumination plane 152 and intersects with bundle axis 148between proximal end 44 of image bundle 42 and recording device 54. Beam142 acts as a carrier for a light channeler located at the bundle axis(not shown) or may serve as a light channeler itself. Light source 144,located at the fixed end of beam 142, is aimed at the light channeler ifa light channeler is present. An illumination path originates at lightsource 144, travels along or through beam 142 to the light channeler,and enters the section of the bundle 42 directly below the channeler. Asthe beam bends back and forth over proximal end 44 of image bundle 42,different portions of image bundle 42 are exposed to the channeler atdifferent points in time. Like embodiments 3-6, this arrangementprovides the opportunity for portions of the image bundle to function atone instant in time as an element which illuminates light transmissionfrom the proximal to distal end of the bundle and as a device forimaging light transmission from the distal end to the proximal end ofthe bundle, at another instant in time. Beam oscillation is accomplishedby means of a driver, or actuator 154, or by the beam 142, itself,depending on the actuation implementation chosen.

Actuators for oscillatory motion include, but are not limited to,slider-crank mechanisms, piezoelectric vibratory actuators,self-actuating cantilever light beams, and exploitation of intermittentmagnetic or electric fields. For rotary motion, actuators include butare not limited to direct drive rotary motors, gear transmissions drivenfrom rotary motors, servo motors, and air drive systems generated eitherfrom a fan or from natural convection currents generated from the lightsource.

Light channelers include but are not limited to the following devices:prisms, fiber optic light guides, transparent disks in which aremachined facets which function as prisms, transparent disks on which arediscreetly placed patches of refractive film causing light travelingthrough the disk to divert out of the disk in the desired direction.

The following embodiment descriptions are examples of how certain lightchannelers could be implemented. Implementations of these lightchannelers are not limited to the embodiments illustrated below.

Oscillatory Motion With Prismatic Channeler (See FIG. 9-1)

In endoscope 160, one or two prisms 162 oscillate within illuminationplane 163 diverting light originating from source 165 from illuminationplane 164 into image bundle 42. As shown, illumination plane 164 isnormal to bundle axis 166 and coincident with light source 165 andprisms 162.

Prismatic Chopler Wheel (See FIGS. 10-1, 10-2, 10-3)

VERSION 1: In endoscope 170 light is channeled via transparent disk 172spinning about axis 188, parallel to illumination axis 174 withinillumination plane 176. Slightly below outer rim 178 of disk 172 atopposite points across illumination axis 174 are located exiting face180 of fixed light source 182 and proximal end 44 of imaging bundle 42.

In outer rim 178 of transparent disk 172 are cut a plurality ofprismatic protrusions 184. When aligned over light source 182, prismaticprotrusions 184 divert light from source 182 into illumination plane176. Disk 172 rotates in illumination plane 176. When located aboveimage bundle 42, prismatic protrusions 184 channel light out ofillumination plane 176 and into image bundle 42. Disk 172 allows lighttransmission between the point at which it is received from light source182 to its target on image bundle 42. Transparent disk 172 rotates indirection 186 about axis 188 in illumination plane 176.

The image transmitted from image bundle 42 through the spaces notoccupied by the protrusions may be viewed or recorded by recordingdevice 54. The viewed image is similar to that seen looking through arotary fan or a propeller.

VERSION 2: In endoscope 190 (FIG. 10-3), transparent disk 192 isidentical to transparent disk 172 except that its center has beenremoved to allow clearance space 194 for light source 196. As in thecase of endoscope 170, transparent disk 192 spins within illuminationplane 198 about illumination axis 200. Light enters image bundle 42through the same means of prismatic protrusions (not shown). located atrim 202 of transparent disk 192. What differs in this version is thelocation of light source 196. Light source 196 is located withinillumination plane 198 at the illumination axis 200, i.e., in the centerhole 194 at the center of the disk described above. Light source 196 isaimed directly at bundle axis 204. Light is transmitted from the centerof the disk to the disk's rim 202 where is then diverted into GRIN lens46, thence into image bundle 42, by-means of the channeling protrusions(not shown).

Fiber Light Channels Mounted to a Wheel (See Drawings 11-1, 11-2, 11-3)

Endoscope 210 is similar to endoscopes 160 and 170 described above withthe following differences. In the place of prismatic protrusions 184, aplurality of fiber optic light guides 212 are positioned overtransparent disk 214. At a given instant, when one end 216 of one offiber optic guides 212 is located over image bundle 42, the other end218 of fiber optic guide 212 is located above light source 182. In thiscase then, the actual light channeler is light guide 212. Transparentdisk 214 acts as a carrier of the light guides, and means to preciselyposition them. In this embodiment, recording device 54 receives theimage from bundle 42 through transparent disk 214 between fiber opticguides 212.

Fiber Light Channelers Mounted to Beam (See Drawing 12-1)

In endoscope 230 light channeling consists of fiber optic light guide232 partially embedded within cantilever beam 234. Cantilever beam 234oscillates within illumination plane 235 about image bundle axis 166.Light may be focused from light source 236 into light guide 232 by meansof a light focusing device 238, such as converging lens(es). Light thentravels through light guide 232, which is mounted to oscillating beam234, to a light channeler 240, such as prism. Channeler 240 is locatedin illumination plane 235 at bundle axis 166. Light entering channeler240 from light guide 232 is diverted into image bundle 42. In endoscope230, light may enter directly into imaging bundle 42 from the channelerinstead of entering a GRIN lens (not shown). If a GRIN lens is employedthe light may be further focused before entering the image bundle. Beamoscillation is accomplished by means of beam driver or actuator 242.

Fiber Light Conductor Mounted to Beam (See Drawing 13)

Endoscope 250 is a further variation of the embodiment depicted byendoscope 230. Except for the details contained herein, it will beappreciated that other elements not depicted are the same. In endoscope250, distal portions 252 of at least one fiber optic guide 254 areembedded within a distal portion 256 of beam 258. Axes 260 of portions252 are parallel with respect to each other. Beam 258 is disposes sothat axes 260 extend into image bundle 42 and such that axes 260 areparallel to axis 148 of image bundle 42. Proximal ends 262 of fiberoptic guides open toward light source 34. Light from light source 34 maybe focused by light focusing device 36. In use, distal portion 256oscillates as shown by arrow 264 generally perpendicular to axis 148,thereby directing light over a variable portion of image bundle 42.

FABRICATION

Fabrication techniques employed in producing above devices include butare not limited to conventional large scale fabrication techniques, suchas milling, turning, molding, etc. Also less conventional means offabrication may be employed such as surface micro-machining, and othertechniques exploited in the production of microelectromechanical systems(MEMS).

Other embodiments are within the following claims. For example, anydevice which receives light from a light source and channels it into adiscrete portion of the image bundle could be used as the lightchanneler.

It will be appreciated that the GRIN lens is used primarily formagnification, and may or may not be present with any particularembodiment in which there is a need or desire for magnification.

While the preferred embodiment describes using light to illuminate thearea to be imaged, it should be understood that other forms of energy,including, for example, UV, IR and ultrasound, could be used for thisimaging.

What is claimed is:
 1. A method of fiber optic endoscopy in which bundleof coherent optical fibers extends from a distal end to a proximal endof an endoscope, the method comprising: conveying an optical image fromthe distal end to the proximal end through filaments of the fiber opticbundle; concurrently with transmission of the image from the distal endto the proximal end, transmitting illumination light from the proximalend to the distal end of the fiber optic bundle through a fraction ofthe optical fibers that are conveying the optical image from the distalend to the proximal end; wherein the fraction of the optical fibers arenotched between the distal and proximal end, the method furtherincluding passing illuminating light through the notches into thenotched fibers to the distal end, image light concurrently movingthrough the notched fibers from the distal end to the proximal end withat least a portion of the image light passing the notch.
 2. A method offiber optic endoscopy in which a bundle of coherent optical fibersextends from a distal end to a proximal end of an endoscope, the methodcomprising: conveying an optical image from the distal end to theproximal end through filaments of the fiber optic bundle; concurrentlywith transmission of the image from the distal end to the proximal end,transmitting illumination light from the proximal end to the distal endof the fiber optic bundle through a fraction of the optical fibers thatare conveying the optical image from the distal end to the proximal end;wherein the fraction of the optical fibers which carry illuminationlight changes as the optical image continues to be transmitted from thedistal end to the proximal end; and wherein the fraction of opticalfibers which carry the illumination light change in a circular pattern.3. A method of fiber optic endoscopy comprising: passing images from adistal end of a bundle of optical fibers to a proximal end; between thedistal and proximal ends, passing illuminating light through notches inat least some of the optical fibers, into and through the notchedoptical fibers to the distal end to provide illumination light;converting the optical image passed to the proximal end of the fiberoptic bundle into an electronic image representation.
 4. A fiber opticendoscope comprising: a coherent fiber optic bundle extending from adistal end to a proximal end; a light source for sending illuminationlight to the distal end of the fiber optic bundle through a fraction ofthe fibers of the fiber optic bundle; an opto-electrical transducer forconverting optical images conveyed from the distal to the proximal endof the coherent fiber optic bundle into an electronic imagerepresentation; notches in a plurality of the optical fibers betweentheir distal and proximal ends; and said light source transmitting theillumination light into the notched fibers through the notch and alongthe notched fibers to the distal end.
 5. A fiber optic endoscopecomprising: a coherent fiber optic bundle extending from a distal end toa proximal end; a light source for sending illumination light to thedistal end of the fiber optic bundle through a fraction of the fibers ofthe fiber optic bundle; an opto-electrical transducer for convertingoptical images conveyed from the distal to the proximal end of thecoherent fiber optic bundle into an electronic image representation;said light source illuminating a fraction of the optical fibers adjacentthe proximal end, the source illuminating light partially obstructingthe opto-electrical transducer; and a mechanism for causing relativemotion between the proximal end of the fiber optic bundle and theillumination light source such that a portion of the optical imageblocked by the illumination light source changes during an imagingprocedure such that all optical fibers of the fiber optic bundlecontribute to the electronic image representation.
 6. The fiber opticendoscope as set forth in claim 5 wherein the illumination light sourceincludes one of a mirror and a prism movably mounted adjacent theproximal end of the fiber optic bundle.